Perinatal mental health is a rapidly evolving specialty concerned with the mental health of childbearing women from conception through pregnancy to the end of the first year after delivery (1). This discipline encompasses clinical and research findings about the correlates and determinants of parental and infant mental health and illness, includes classification and diagnostic issues, methods for prevention, early intervention and treatment, impact, and outcome studies. The pivotal role played by parental mental health in the physical, emotional, cognitive, social and behavioural development of infants is widely acknowledged (2–4) and international Public Health programmes are being aimed increasingly at strategies that will reduce current high rates of mental health morbidity in this population (5).

Many early studies of mental health amongst childbearing women dealt exclusively with postnatal symptoms, especially postnatal depression (PND); however, rates of elevated scores (12–13 cutoff) on the Edinburgh Postnatal Depression Scale (EPDS) (6) that have been shown to correlate with a formal diagnosis of clinical depression have been found to be similar during pregnancy and after delivery. Up to 40% of women have both antenatal and postnatal symptoms, which suggests for many there is a continuum of distress (1). The EPDS is also sensitive to anxiety ‘the blues’ and stress-related symptoms, thus high scores indicate the need for further assessment to establish the correct diagnosis. Anxiety disorders are being increasingly documented with recent studies suggesting that perinatal anxiety may be as common as perinatal depression (1). Studies highlight the presence of considerable comorbidity, the confounding effects of drug and alcohol abuse, eating disorders, and personality, upon perinatal mental health (7) and one recent British report cites suicide as the leading cause of maternal death postpartum in association with severe psychiatric illness (8).

Evidence is emerging concerning the impact of antenatal maternal distress upon foetal and infant behaviours and indicates the possible role of the hypothalamic pituitary adrenal axis in the transmission of maternal distress to the offspring in utero (9). Research that has previously addressed the impact of PND on infants may be significantly confounded by the in utero influence of antenatal maternal anxiety and depression (9, 10). The influences of antenatal and postnatal mood and anxiety disorders need to be more clearly differentiated, as do environmental and genetic factors.

The majority of impact studies have demonstrated that PND is associated with adverse cognitive, emotional and behavioural outcomes in infants and problematic parenting behaviours. ‘Suboptimal’ parenting behaviours are not confined to parents with depressive disorders and adverse outcomes for infants may persist beyond the duration of the initial parental episode of mental illness (1, 2, 11). Links between PND and reduced infant growth rates in Asia have recently been demonstrated in combination with high rates of PND leading to speculation that depressed women in Third World countries may have difficulty attending to their own physical and emotional health care needs as well as those of their infants (5).

Strategies for screening, prevention, early intervention and treatment

The identification of antenatal risk factors associated with PND has failed to produce risk indices that have adequate sensitivity or specificity for the prediction of PND. This has led to recommendations that antenatal psychosocial screening programmes focus on early identification, preventive and early intervention strategies rather than prediction of PND (1). Screening during pregnancy is important in its own right given that many women show symptoms that are amenable to interventions to reduce maternal distress and risks for the infant in utero (12). Universal antenatal psychosocial screening programmes are being trialed in a number of centres using combined approaches that include scores on self-report measures of symptoms and psychosocial risk factors (1, 11, 12). Postnatal psychosocial screening indices are being evaluated to aid in early postnatal identification of women ‘at risk’ (13). Given that most women seek health care services around pregnancy, delivery and the early postpartum, psychosocial screening fits well into a primary prevention framework provided adequately trained staff are available to screen and provide follow-up services to those identified as being ‘at risk’ (1, 13).

Antenatal and postnatal prevention, early intervention and treatment programmes

Randomized controlled trials evaluating antenatal group interventions for ‘selected’ populations, aimed at prevention of PND have had methodological shortcomings and variable outcomes (14). Some psychological interventions targeting women with high postnatal EPDS scores have led to improved maternal mood in the short term but no demonstrable improvements in mother–infant relationship, cognitive development or other child outcomes nor was any reduction in rates of maternal depression at 5-year review (3, 4). A recent study using cognitive behavioural therapy with women meeting DSM-IV criteria for diagnosis of depression showed sustained improvements in maternal mood and adjustment at 1 year after delivery (15). Further knowledge is required on the safety of psychotropes in the perinatal period, and clinicians need to carefully discuss and document the risk–benefit ratio of pharmacological treatment and prophylaxis with all prospective parents (16).

There are major challenges still to be overcome at a global level in relation to measures, diagnosis, impact of disorders, psychosocial screening, prevention, early intervention, treatment, and outcomes if perinatal mental health morbidity and mortality are to be reduced.